Wall plug



N. SLUYTER Nov. M, @1933,

WALL PLUG Filed March 9, 1932 NBCOLA'Afi SLUYTER INVENTOR 6; 1 4:

ATTORNEYS Patented Nov. 14, 1933 s'ra'rss Application March 9, 1932, Serial No. 597,?8d,

and in the Netherlands April 20, 193i 3 Claims. (GE, 852.)

This invention relates to a tubular wall-plug and has for its object to make it exceedingly simple and strong at a low price and adapted to exert a firm clamping action in the hole in the wall.

In its broadest aspect the invention consists in this, that a tubular one piece wall plug or anchor sleeve is provided with internal screw thread for the reception of the screw W thread of a member, e. g. a screw or bolt, that is to be held by the plug, the latter allowing radial expansion caused by relative axial movement of said member into the plug. In a preferred embodiment the one-piece internally threaded tubular plug may be provided with longitudinal slots, one or more of which start from the one, the remainder from the other end oi the plug which slots may continue till near the opposite end of the plug. Objectionable expansion only at one end of the plug is thereby ob viated because the slots do not start at one but at both ends of the plug.

This has the great advantage, that the plug, after being pressed totally in the hole in the stone to the bottom thereof will expand itself in the heart of the stone during the screwing in of e. g. a wood-screw (or in general a member the screw-thread of which in cooperation with that of the plug causes expansion of the plug) 39 and besides will work along the screw thread in the direction of the head, (self locking expanding plug). A clamping over almost the whole length of the plug in the heart of the short plug in proportion to the length of the screw can be used. The invention will be fully described with reference to the accompanying diagrammatic draw-.

ing, in which: I

Fig. 1 is a side view of a wall-plug according to the invention.

Fig. 2 is a plan view of the same. Fig. 3 is a sectional view of a wall-plug according to the invention inthe heart of a stone before and after the clamping by means of a woodscrew. V

Fig. 4 is a perspective view of the plug. The wall-plug, represented in the drawing in 513 the form of a small metal tube or sleeve, for

example, of copper, is provided with alongitudinal groove '1, starting from the end 2 of the plug and a longitudinal groove 3' starting from the other end a of the plug. lhe ends 2 and d or the plug, as clearly shown in the drawing, are

. project outside the stone.

tapered inwardly. This permits either end of the plug to be easily inserted.

The longitudinal groove 1 continues till near the end 4; and the longitudinal groove 3 till near the end 2 of the plug. Moreover the plug is provided with internal screw thread 5.

The exterior oi. the central part 7 of the plug has milled notches or longitudinal grooves 6, which part can have, if desired, also the same diameter as the other part of the plug.

Fig. 3 shows a wall-plug according to the invention, situated into a hole 9, which has been inserted into a wallstone 10. The plug is placed in the bottom of the hole in the heart of the stone l0 and a wood-screw 1.1 is screwed into the plug, securing a plate 12 on to the stone 10.

The wall-plug is used'as followsz-=- After the'desired hole is made into the stone, according to the maximum diameter of the plug and the length of the screw or bolt, the plug is pressed into the hole until its front end does not Then the article to be fixed is held in place against the stone after which the screw or bolt is screwed in by some turns with a screw-driver or screw-wrench. Now the screw or bolt with the plug connected to it, is driven to the bottom of the hole, after which the screw or bolt is screwed fully in.

In consequence of the conical form of the screw or bolt the plug is radially expanded owing to the screwing up of the plug on to the conical screw when the same is screwed in so that the plug clamps itself in the wall of the hole in the stone, the clamping actionpreventing .rotation of the plug with the screw or bolt. 1

Owing .tothe grooves starting from both ends of the plug, the clamping action will extend over the total length of the plug and as indicated in Fig. 3 in the heart of the stone.

in hard walls, for example, of freestone, concrete, hard kind of stones, etc., the plug will stick fast already after some turns of the screw-driver or screw-wrench; in softer walls some more turns are necessary, as the softmaterial allows more expansion of the plug.

The fastening is quickly done, although when desired the plug can easily be taken out again by unscrewing the screw or bolt a little and slightly striking the same on the head. Then the plug can be used again.

One linear measure for the screw or bolt can housed for diflerent thicmesses of the objects to be fastened.

Also the same size of screw can be used for hard as well as for soft walls. Breaking of the plugs practically does not occur and the fastening does not require any special professional knowledge.

It will be understood that the invention is not limited to wall plugs of metal but that wall plugs made of other suitable hard materials, e. g. hard rubber, fall within the scope of the invention.

Further it is possible either to use a single conical screw-thread having the same conicity as the screw thread of the member to be held thereby, or to use a screw-thread comprising two or more portions having different diameters, e. g. a narrower and a wider portion, in particular in wall plugs adapted to receive screws.

The plug and the. member to be held thereby may have screw threads having the same taper or alternatively may have screw threads being relatively tapered so that in both cases relative axial movement of the member into the plug causes expansion of the latter.

The invention is not limited to the use of slotted plugs. The plug might be made of rubber or a rubber compound allowing radial expansion and adapted to be provided with internal screw thread adapted to cooperate with screw thread of a member to be held by the plug for the purpose and in the manner described.

I claim:

1. Anchoring means for a screw comprising a unitary substantially cylindrical hard metal sleeve having an-internal screw threaded bore. said sleeve having a pair of diametrically opposed slots therein connecting said bore with the exterior of the sleeve, said slots extending from one end of the sleeve to points close to but slightly spaced from the second end of the sleeve, said sleeve having a second pair of diametrically opposed slots having the plane of their longitudinal axis substantially perpendicular to the plane of the longitudinal axis of the first pair of slots, said second pair of slots connecting the bore with the exterior of the sleeve and extending from the second end of the sleeve to points close to but slightly spaced from the first end of the sleeve, and a plurality of longitudinal ridges on the external surface of said sleeve intermediate its ends and extending radially outward from said surface to prevent rotation of the sleeve and to provide for axial movement of said sleeve a certain distance in the hole in which the screw is to be anchored.

2. Anchoring means for a screw comprising a unitary substantially cylindrical hard metal sleeve having an internal screw threaded bore, said sleeve being beveled inwardly at each end and having a pair of diametrically opposed slots therein connecting said bore with the exterior of the sleeve, said slots extending from one end of the sleeve to points close to but slightly spaced from the second end of the sleeve, said sleeve having a second pair of diametrically opposed slots having the plane of their longitudinal axis substantially perpendicular to the plane of the longitudinal axis of the first pair of slots, said second pair of slots connecting the bore with the exterior of the sleeve and extending from the second end of the sleeve to points close to but slightly spaced from the first end of the sleeve, and a plurality of longitudinal ridges on the external surface of said sleeve intermediate its ends and extending radially outward from said surface to prevent rotation of the sleeve and to provide for axial movement of said sleeve a certain distance in the hole in which the screw is to be anchored.

3. Anchoring means for a screw comprising a unitary substantially cylindrical hard metal sleeve having an internal screw threaded bore, said sleeve having a group or plurality of spaced slots therein connecting said bore with the exterior of the sleeve, said slots extending from one end of the sleeve to points close to but slightly spaced from the second end of the sleeve, said sleeve having a second group or plurality of similarly spaced slots having the-planes of their longitudinal axes disposed at symmetrical angles with the planes of the longitudinal axes of the slots of said first group, said second group of slots connecting the bore with the exterior of the sleeve and extending from the second end of the sleeve to points close to but slightly spaced from the first end of the sleeve, and a plurality of longi-' tudinal ridges on the external surface of said sleeve intermediate its ends and extending radially outward from said surface to prevent rotation of the sleeve and to provide for axial movement of said sleeve a certain distance in the hole in which the screw is to be anchored.

NICOLAAS SLU'YTER. 

